Conventional rural power transmission networks provide electrical power through high voltage power transmission lines, which are mostly Aluminum Core Steel Reinforced (ACSR) lines. Power transmission lines normally leave a power station and connect to substations in outlying rural areas. These lines typically carry a distribution voltage of 360 KV. At the sub-stations, a power transformer is used to step down the distribution voltage to 7620 V. Lines from the sub-stations go to communities or homes, where the voltage is further reduced by another power transformer, usually to 240 V single-phase.
The power is transmitted in the form of time-varying voltage and current. The time-varying current flowing through a power transmission line causes electromagnetic radiation to emanate from the line. The radiating electromagnetic radiation produced by the motion of electrically charged particles includes an electric field component and a magnetic field component that are interdependent, with a change in one accompanied by a change in the other. This relationship is governed by Maxwell's equations.